Does Permaculture work?

Hello!
I have to say, this mailing list is an incredible resource. Thank you to
all who have taken the time to respond to my questions!
I have another one:
Have any of the CSA's or other farms on this list intentionally or
unintentionally used principles from Permaculture in your farm's planning
or production?
I gave a presentation to my Senior Seminar in Environmental Studies on
Permaculture, and my fellow students were inspired by it. However, I spoke
mostly about the theoretical or examples of what could be, and received
several comments that they would like to know about how it works in real
life. The perfessor is particularly interested in whether permaculture is
applicable on a large scale, or if it requires too much management. Others
were interested in knowing if the same area of land really could be more
productive, either in biomass or cash terms, than the same area under
conventional agricultural practices.
Can anyone put in a few words?
Thanks!
Becca
bshapley@brynmawr.edu